Pharmacology Mnemonics - Flash Cards

Name: Mexiletine (Mexitil)

Class: Antidysrhythmic Agent (Class IB)

Mechanism: Shortens phase 3 repolarization. Decreases action potential duration. Inhibits arrhythmias caused by abnormal automaticity. Rapid speed of dissociation from Na⁺ channels.

Absorption: Oral

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s: Proarrhythmic effects, negative inotropy, infranodal conduction block. N/v, dizziness, disorientation, tremor.

Utility: Chronic treatment of ventricular arrhythmias assoc. w/previous myocardial infarction.

Special Features: Concurrent use w/quinidine may be effective at lower doses than either alone ® ¯ adverse effects of each.

Name: Tocainide (Tonocard)

Class: Antidysrhythmic Agent (Class IB)

Mechanism: Shortens phase 3 repolarization. Little change in action potential duration. Inhibits arrhythmias caused by abnormal automaticity. Rapid speed of dissociation from Na⁺ channels.

Absorption: Oral

Dist.:

Metabolism.:

Excretion, t½:

Toxicity/S.E.s: Proarrhythmic effects, negative inotropy, infranodal conduction block. N/v, dizziness, disorientation, tremor. Hematologic effects (agranulocytosis, bone marrow suppression, thrombocytopenia) can be fatal.

Utility: Treat ventricular tachyarrhythmias (only as a last resort).

Special Features: Concurrent use w/quinidine may be effective at lower doses than either alone ® ¯ adverse effects of each.

Name: Lidocaine (Zylocaine)

Class: Antidysrhythmic Agent (Class IB)

Mechanism: Shortens phase 3 repolarization. Little change in action potential duration. Inhibits arrhythmias caused by abnormal automaticity. Rapid speed of dissociation from Na⁺ channels.

Absorption: IV

Dist.:

Metabolism.: Hepatic.

Excretion, t½:

Toxicity/S.E.s: Fairly wide therapeutic index. Proarrhythmic effects, negative inotropy, infranodal conduction block. Drowsiness, slurred speech, paresthesia, agitation, confusion, convulsions, resp. depression, tinnitus, muscle twitching, psychosis, seizures. ­ CNS toxicity if used w/tocainide or mexiletine (e.g., seizures).

Utility: DOC for sustained ventricular tachycardia. Treat ventricular arrhythmias arising during myocardial ischemia or digitalis-induced VA.

Special Features: Class IB drugs have the lowest potency as Na⁺ channel blockers.